Cardiac function management systems are used to treat arrhythmias and other abnormal heart conditions. Such systems generally include cardiac leads implanted in the heart for delivering an electrical pulse to the cardiac muscle, for sensing electrical signals produced in the cardiac muscle, or for both delivering and sensing. The lead typically consists of a flexible conductor defining a central channel or lumen surrounded by an insulating sheath extending from an electrode at a distal end to a connector pin at a proximal end.
Cardiac lead placement may be accomplished by introducing the lead through a major blood vessel and advancing the distal end of the lead to a final destination in or near the heart. To facilitate cannulation of the vasculature, it is often helpful to first advance a guide catheter through the desired vascular path. The guide catheter must be sized to accommodate the lead and to provide sufficient support, alone or in combination with a stylet, as the lead is advanced through the vasculature. Such guide catheters are often too awkward or bulky to successfully and efficiently navigate the very small distal lateral branch vessels of the coronary sinus. Another difficulty with implanting leads in this fashion is that the cardiac lead has a tendency to become dislodged during guide catheter removal.
Another difficulty with cardiac lead placement is that a traditional lead may be too bulky for placement into narrower vessels. Even if placement of the lead is possible, the lead may block or impede fluid flow through narrower vessels to an unacceptable degree.
Accordingly, there is a need in the art for a reliable low profile lead and lead implantation system that does not necessarily require the use of a guide catheter. There is a further need for a lead implantation system that may also serve to anchor the lead at the implant site.